Large-scale thallene film with emergent spin-polarized states mediated by tin intercalation for spintronics applications

The quantum effects confined in the ultimate two-dimensional limit are able to address the challenges and provide advances in high-performance spintronic devices. In the paper we show a successful strategy to enrich the electronic properties of thallene, a new honeycomb analogue of graphene, through the interface engineering, which opens a great potential of thallene as an advanced spintronics material. While the thallene has been experimentally realized recently on NiSi2/Si(111) substrate, there remains a lack of attractive electronic properties due to the strong thallene-substrate coupling. This challenge is addressed here through the decoration of thallene/NiSi2 interface by Sn interlayer, which allows to eliminate the thallene-substrate coupling and produce a high-quality large-scale thallene monolayer with exotic electron bands demonstrating colossal spin-polarization just above the Fermi level. It is demonstrated that appropriate electron doping or external electric field are enable the spin-transport regime. The discovered band structure regulation boosts the functionality of the 2D-Tl Xene and makes it a highly attractive material for spintronics applications.